Control of aircraft



- O. H. D. V-ICKERS ET Al.

CONTROL OF AIRCRAFT Filed Oct. 27

.G-al

1 Nov. l, 392% nmnr noueaas vrcnms em) neu'nrcn KERR rneonnnv, or r non, ENGLAND, essreno 'ro vrcnnns Lrrar'rnn, or LONDON, nner.

is: THIN 8'1 has.

oorrrnon or arnonarr.

Application filled October 27, 1922. serial No. 597,242.

To all whom it may concern:

"Be it known that we, OLIVER HENRY Dono- LAB Views and MAURICE INooLnnY, both subjects of the King of Great Britain,

residing at Viokers House, Broadway, Westminster, in the county of London, England, have invented certain new and useful Improvements in or Relating to the Control of prising a small pump unit of the variable delive t e, as employed for example in the VglliZ s-Janney hydraulic gear, and a double acting hydraulic ram connected to the said pump andprovided with a leakage 'usted to give the desired displacement on ad 'ei or side of the mean osition according t lation of the elivery control of' o the the plump unit. Three servo-motor systems of t s type are provided respectively for fore and aft control, lateral control and directional control and for the manual control of the aircrai t by the pilot either the control column and rudder bar or an auxilipose sensitive gear is ables the pilot to feel directly the extent to which the various control members are under tension. To give the required sensitiveness a device is provided for each control lever that is some fraction of the actual effort of the servo-motor and a convenient method of 'ving such back pressureto the control ever in a servo-motor sym of the kind above described is to carrya small'by-pass at each end of each of-thegrams from the supply pipes leading to the tame and to ctuate by these by-passes a small diaphi agm v fully drawings, in which A A are operated I hand control lover or double piston device connected to the control lever in 1 the direction in which this lever is moved for the particular control in question,

The servo-motor control may also be pro.- vided with means by which it can be thrown out of action instantly; and the ordinary manual control established.

In order that the said invention may be clearly understood and readily carried into efiect, the same will now be described-more with reference to the accompanying Figure l is a diagram showing the general I I arrangement of aservo-motor system for aircraft control embodying the present invention; and

Figure 2 is a, detail view showing a device for changing over the servo-motor control to direct control.

. A, A A are, the pump units of three hydraulic gears of the RWilliams-Janney type.

B, B Bf'are three yhydraulic rams corre sponding to the pump units and connected at opposite ends to the pps by the connections 6, b. C, 0 G are the control surfaces of the air craft, C representing ailerons or equivalent devices for lateralcontrol, C a horizontal rudder for fore. and aft control and C vertical rudders for directional control. I D, D, D are flexible driving connections or cords between the pistons 6 and piston rods 1) of the rams and the control surfaces 6, G, C", the cords passin over the pulleys d, al (i so that the contro surfaces are operated in opposite directions according to the direction in which the flexible connections D, D, D are pulled.

E is an electric motor and F is a fan driv-' ing mutually the three pump units A, A, A through the fan or propeller shaft f and the gear wheels f, the motor E driving the fan shaft through the chain gear e. livery control levers a, a of the pump units b the hand wheel G and G throughthe rods g, g and. lever arms g, g. The arm 9 18 on a spindle g? and turned through the chain gearingg" from the hand wheel G; while the arm g may form a continuation of the hand lever 9 The delivery control lover a of the pump A is operated b the lever Gr acting throu h the rod 9 an arm- 9',

- H, H H in icate three-motor units of the hydraulic gear which can be employed The de-' for any operation required when the aircraft control system is not in use, the motors H, H H serving, ton example, for starting the aircraft engine, working bilge pumps, pumping petrol, or in the case of an amphihian machine operating the retractable under-carriage. They are connected to the pump units A, A A by the tubes h, it promatically' onl required.

vided with valves it under the control of hand levers it by which each motor can be connected up with the system or cut off as J are valves under the common control of a hand lever j, provided in the entire set of tubular connections leading from the pump units to the rams and motors. allowing the rams to be cut oil from the pump units at a single operation and the auxiliary motor system H, H H to be connected up. K is a reservoir connected up by the pipes 7a to the pump and motor casings.

en the aircraft is in flight the pump units A, A A may he driven entirely by the passage or air past the fan F, the motor E heing cut out, or both the motor and fan may he in operation simultaneously. If the apparatus is required for driving auxiliary motors when the aircraft is not in tlight the drive may be entirely from the motor ll.

Each of the rams B, 13 B has a double acting piston 25 under the control of springs 6 and provided with a leakage aperture 5 with a choke rod 2') giving a variable leak between the two ends of the ram cylinder, which as shownare connected to the opposite sides of the corresponding pump unit so that liquid is forced in by the pump at one end of the ram cylinder and is withdrawn/at the other at a rate corresponding to the adjustment of the control levers a, a

a which operate the usual swash plate or equivalent device varying the del very of the pump from zero to a maximum in either direction. 'lhe springs I? tend to return the piston b to its central osition with a force dependin upon the replacement of the piston and t e choke rod 6 isso shaped relativel to the aperture 6 in the piston as to give t e desired ratio of movement of the ram relatively to the adjustment of the pump unit. The rams are shown diagramand any ol-the variable-leak devices described in ecifigcation No. 30053 or 1921' above refer-re to may he employed.

The arranment of flexible connections -01 iagrammatic and may he taken to represeirit any connections. hetween the various aircraft control surtaces C, G, C and the ram pistons. With the arrangement ot wires or cords and pulleys indisated it-will he seen th t it the piston b of the ram 3B is moved in one direction the derilole connections will operate in one sense on the ailerons C, while it the movement of the piston is in the opposite direction the aileilddildddl rons will he displaced in the opposite sense to an angle depending on the oisplacement of the piston, Similarly with the other controls of the aircraft the movement in sense and extent will depend upon the direction and amount of displacement oil the corresponding ram piston and as the variation of the choking effect of each ram can be ad-i cylinders Z of which are connected by the pipes Z to the pipes or tubes 6, b leadingv from the two ends of the rams to the two sides of the pump units. The pistons are connected by the rods Z to the lever arms 1 g and g of the respective hand control devices sothat the pilot for every control operation will feel a response to the manual movement depending upon the fluid pres= sure in the servo-motor system, that is, varying with the actual force employed to operate the control surfaces. v

It it should he desired to throw the servomotor system out of action and establish ordinary manual control in its place a device'such as is indicated diagrammatically in Figure 2 may be employed, in which cords or wires D connected to the opposite ends of the piston rod of the ram pass over pulleys 02 and are attached to the operatin cord or wire D which double pulleys are arranged to be movable towards and away from each other, preferably moving in one direction under the control of a spring. The wires D also pass over the stationary pulleys 0Z When the pulleys d are drawn towards one another the wire it)? is kept taut and the ram can operate the control wire l). The wire. l is connected both to" the control surface or the aircraft and to the manually operated lever indicated diagrammatically at G, The wire D is arranged to form a loop passing over the stationary .movahle pulleys 0Z Vhen the pulleys ol are drawn towards each other the loop of the"wire D is slack wire D is taut, but when the pulleys d are separated the loop D is tightened and the; ram connection D is slackened, so that the ramis inoperative and'the control is then a plurality of control surfaces an independ .ent servo-motor system for each control ulleys d and the while the aumiliary lllll lltl llli

iao

Lemma surface, a source of power for the said servo-motors, means under the operation of the pilot for adjusting the work of each of the said servo-motors, and a sensitive-gear interposed between the servo-motor system and the mechanism under the operation of the pilot, whereby aresistance is offered to the' pilot-operated-mechanism varying with the range of the control operation.

2. In a control mechanism for aircraft, a

plurality of control surfaces, .a hydraulicservo-motor system for each control system,

which servo-motor system comprises a variable delivery pump vand a motor, a source of power driving the said variable pump, and means operated by the pilot for varying the delivery of each pump and consequently determining the movementof plurality of control surfaces, a hydraulic servo-motor system for each of the said surfaces, which system comprises a variable delivery hydraulic pump and a double acting ram with resiliently controlled piston Q and a variable leakage channel from one.

side to the other of the said piston, a source of power for the said variable delivery pump and means under the operation of the pilot for varying the deliveryof the pump and consequently determining the movement of the corresponding control surface.

4. In control mechanism as claimed in claim 3, flexible connecting means between the said double acting ram and the corresponding aircraft control surfaces, direct flexible connections between the same surfaces and the mechanism operated directly by the pilot, and means whereby the said flexible connections from the ram and thepilot operated mechanism are alternatively tightened up and sla ckened, whereby the air craft control surfaces are placed at will under the control 'of the hydraulic ram or of the pilot operated mechanism.

OLIVER HENRY DOUGLAS VICKERS. 'MAURICE KERR INGOLDBY. 

